Signaling system for railroads



Aug. 7, 1934. J. BENNETT SIGNALING SYSTEM FOR RAILROADS Filed Feb. 4, 1952 Nvwww BY ATTORNEY Patented Aug. 7, 1934 1,969,058 SIGNALING SYSTEM ron nAILRoAns f Jerry Bennett, Scottsville, N. Y., assigner to Gen# IeralV Railway Signal Company, 1 Rochester,

Application February 4, 1932, Serial No.1590,89g

'5 claims. 01.' 24e-ijn" rli'his invention relates to railway signaling, and constitutes another species 'of the invention disclosed in the prior application of Walter W. Wenliolz Ser. No. 500,802 filed December 8, 1930,

5 and is 'an improvement subordinate to theA invention disclosed in said Wenholz application.

It is quite common in railway signaling practice to use direct current polar relays for transmitting conditions of traiiic from a particular Signal to the next signal in the rear. Also, it is Well understood thatra direct current 'polar-neutral relay upon a change of polarity in the current for energizing the same, Will cause the neutral armature to drop momentarily, this irrespective ol" whether the relay is a slow acting relay and irrespective of how quick the change in polarity is made. The dropping of the neutral armature is attributed Vto a reversal of the ilux in the core structure of the relay, leaving the neutral armature 'unattracted during 'such 'reversal. Since the polar position of a home-distant relay of lone signal is controlled in accordance with the 'energized condition ofthe hornedistant relay of the next signal in advance in a signal system of the type above mentioned, it is apparent that pole changing oi'one honte. distant relay will cause momentary opening of the circuit of the next 4herne#distant 'relay in the rear, and so on to the end of the railroad, or to a point Where there is a trainto break up this tumble down effect. This successive'dropping of yironie-distant relays is commonly known among signal engineersas a kick-oit. In former systems of signaling such kick-orf has been prevented by the addition of a repeater relay which in most cases is slow acting and which repeater relay would repeat only fdeenergization (not pole changing) of the home-distant relay, it havingY been experienced that to make the home-distant relay slow acting wouldnotprevent the kick-off occurring.

Inaccordance with the present invention it is proposed to construct the neutral portion of the homedistant relay to permit elimination vof repeater relay, by: employing as a home-distant relay in a system of .the type mentioned,Y a polar neutral relay ofi the neutral-retainetcl-armature type in which the neutral armature has an auxiliary electromagnet which is inductively connectedeither tothe circuit for the main magnet oi-is ,inductively connected to the.lwinding..of the main magnet, this neutral-retainedannature relay being constructed-so that the neutral armature will' notmornentarily drop during the reversal of the currentin the relay circuit.

Other objects-purposes and character'isticfea# tures ofthe present invention will infpart be pointed out hereinafter and l'vvilllin 'part be ap- 'parent from the accoinpanying drawing. Y

The accompanying drawingv shows one'mbodiment of the present-inventionas apphe'to a double track krailway signa'img system, in which the trackway is signaledV for one d'ireeftioiV di trarne only.

Referring to the drawing,` the` trackfrail's 'l have Vbeen shown divided by insulating ici-nts 12 into blocks, of Which the block I andthe rtjl 'Cent endsf the blO'Ck I-l 'lli J Ollly :have been illustrated. Each of these blocks includes the usual track battery 4 and a track relay T. VAt the entrance end of 'each block, nor-mal 'direc-'- tion of tralc being' from left to right, tllttf West to east, is located 'a vsignal S V'of thernultiple aspect light signal typ`e,jincluding a clear signal laninG, a cautionsignal `lamp Y and a danger signal lamp R, 'emitting when energized light beams of green, .yellow and' red, respectively. Since the apparatus 'for reach of thevarious blocksA is the, same 4thisapparatus will :be 'described only `for the A'block I, like parts being iles'- ignated 'by like reference cln'aifactersv having 'dis tinctive exponents.v .1 f v The 'signal S has. associated therewith 'a h'oni'L distant relay HDR kand 'an 'approach relay the home-'distant 'relay-HDR being used to 'control the selection fof the'fparticular light signal 'unitto-'be illuminated, andA the approach `lightling' relayAL being 'usedto 'cutenergy 'olf of all of the three light signal units under conditions when .no signal is required, this in order to 'save energy. Under normal clear traffic conditions' in ad- Vance? 'of thesignal 's the home-distant relay -HDR is"energizecl-y by "current 'of positive 'polarity gil' front contact 14 lof4 the 'tracli' relay ,"T," wir@ l5,

terminal ngt-)persan hatte-wg It is believen that the nov'ifeaturesef' 'the system @an be during the passage'oi a train. 4 Y v c operatief?" t `Let u's assumethat'there is a ltrain approach; ing signal S 'inf'the blockJI-I moving "frein left explained by considering the operation' thereof Mz c t 105 itt ,65, polegchangingof the Vrelay HDR. -V 'Y v circuitof the relayf-HDR through'the ymedium indicated by the arrow; the entrance of the train intothe block H will cause opening of the line circuit 13 kdue to dropping of the front contact i14" (not shown) of the track relay T" (not shown), thereby causing dropping of the approach 'lighting relay AL, and closure of itsr back contact 27.

HDR, wire 23, polar contact 24 to the right, wire 25, green lamp G, wire 26,*back contactnz'? of relay AL, to the other terminal BVv (v--).V The completion of this circuitwill of course illuminate the green lamp G, to 'inform the engineer of the approaching train that traic conditions in advance are clear.

As the train accepts the signal Sand passes into the block I the track relay T is deenergized;

thereby effecting deenergization of the relay HDR,j'and eXtinguishment of theyclear lamp G of the signal S andfalso illumination of the red lamp yR through the following circuitz-beginning at the terminal B back Contact 220i relay HDR, :wire 30, Vred klamp R, wire 26, back contact 27 of relay AL, to the other terminal B Asthe train in question passes from theV block lI into the block J, signal S1 will cause, deenergization of relay HDR1, which will result in its red lampR being energized and its green lamp G being deenergized, in a manner as already explained in connection with` signal S. Also, as the rear end of the train passes out of theblock If'the home-distant relay HDR is energized by current of negative polarity through the same circuit heretofore traced with the contacts 12 and 21jassuming their retracted position, thus relversing the direction of current flow. With the `relay HDR energized "by Vcurrent of negative polarity, as is now the case, its polar contact 24 will assume the dotted position, so that if a train'were toenter-thevblock Hand effect de#- energization of the approach lighting relay AL, the caution lamp Y of signal S Will beilluminated through va circuit including the Vpolar contact 24'fof relay HDR andV Wirei28, thereby informing the engineer of the train in `the'block kH 'that the ysecond'block in advance, namely the block ,J; `is voccupied-by another'train.

nAs the train'in question now passes out of the'vblo'ckJ therelay HDR? is energized iby cur'- rentfof negative polarity `'to effect operation of its contact'241 yto the left, thereby lighting the 'caution-lamp Y of Asignal S1, all-in a manner as already explained in connection "with the relay HDR. Picking up of the contacts 12 and 21 of relay HDR1 will cause a sudden reversal ofpolarity-in thecurrent applied to the'relay HDR, but -thissudden reversal of polarity ofl the'current in the main winding 16 of the relay HDR will not result in momentary 'dropping of the contactsl2 and-21 of this" relay, so` thatvthejnexthome? distant -relay inV thegrear (home relay HDR", not shown)A will not in any ,way be. affected by the ---'Itfmay-be pointed out here that the relay HDR, includes an--auxiliary magnet-comprising `a core V40 -havingafwinding -41 thereonfwhich winding 7.5.. Yauxiliary electromagnet; a By'. this arrangement 4L is inductively linkeduwithl the main magnetic of the secondary Winding42. Iny other words, the main core of the relay HDR contains a winding 16.,` and. af; secondary winding 42, `'and` this latter winding-is connected .to`thewinding 41 of the the collapse of the flux in the main core structure of the relay causes a current to be induced in the auxiliary winding 41 of the relay, and this induced current produces a iiux in the core structure 40, thereby holding the neutral contact 12, 21 and 22 all in an attracted position during the time that such induced current flows. It-.may be pointed out .that this induced current is not only due to the collapse of the flux in the main core structure, but is in part due to 'the building up of new flux in the main core in the reverse direction, from which itis apparent that "the auxiliary electromagnet 40-41 will receive a substantial amount of energy, and

kthis energy Aispresent for a suflicient period of time to allow the main magnetic circuit of the relay to Vagain hold its neutral armature attracted by the new current of reverse polarity.

It is thus seen that the reversal of current from negative to positive, or vice versa, in the circuit rof a home-distant relay will not result in momentaryv opening ,ofv the` circuit for the next home-distant relay in the rear controlled by the rst mentioned home-distant relay, vso that the undesirable kick-off heretofore mentioned is entirely absent. It may also be pointed out that asan auxiliary feature of the present invention, pole changing of `the relay, such as relay HDR, from negative to positive polarity causing move.i ment of the contact 24 from its dotted to its solid line position, causes the yellow lamp Y to be eX- tinguished and the greep lamp G to belighted withoutin the meantime momentarily energizing Y the red lamp R', it thus avoids, what is known in signal parlance as ashing of the red, during a change from caution to clear, and vice versa.

Having thus shown one particular embodiment of the present invention, it is desired to be understood that the invention is not limited to the vparticular type ofsystem as shown in the drawing, and. that additions, modications -and changes may be made rto adapt the invention to the particular signal. problem encountered in practicing the same, allwithout departing from lthe spirit of the present invention or its scope, except as demanded bythe/'scope of ,the followingclaims. I 'Y WhatI claimasnewisz- L .Y

1. In a polar direct current signaling system of the multiple aspect light signal type; the combinationwith a railway track having successive threeaspect light signals associated therewith, of a relay having a polar armature which'assumes a position depending upon the polarity of current last applied to its mainwincling, a. neutral armature and contacts, and a winding for'the neutral armature deriving magnetism from said main winding, associated with each signal vccnltrolling such signal rto indicate clear, caution and danger, when such relayisv energized positively, negatively and de-Kenergized respectively; "and an energizing circuit for eachof said relays including pole changing contacts operated by suchv `neutral armature of the relay associated-with a polar neutral-retained relay associated with each" signal, each of'which relays has arraux iliary electromagnet acting on the neutral'arinal ture thereof and connected inductively to the circuit of the main Winding of such relay, and controlling such signal to indicate clear, caution and danger, when such relay is energized positively, negatively and deenergized respectively; a circuit for each of said relays including neutralretained armature pole changing contacts operated by the relay of the next signal location in advance arranged so that the direction of current flow in such circuit is reversed When the relay in advance is deenergized, and means for deenergizing a particular relay if the block neXt in advance of such relay is occupied by a train.

3. In a polar direct current signaling system of the light signal type; the combination with a railway track having successive light signals associated therewith; a polar neutral-retained relay associated With each signal, each of which relays has an auxiliary electromagnet acting on the neutral armature thereof and connected inductively to the circuit of the main winding o such relay, and controlling such signal to indicate clear, caution and danger, when such relay is energized positively, negatively and deenergized respectively; and a circuit for each of said relays including neutralretained armature pole changing contacts operated by the polar neutralretained relay located at the next signal 1ocation in advance arranged so that the direction of current iiow in such circuit is reversed when said relay in advance is deenergized.

n 4. In a polar direct current signaling system of the light signal type; the combination with a railway track having successive light signals associated therewith; a polar neutral-retained relay associated With each signal, each of Which relays has an auxiliary electromagnet acting on the neutral armature thereof and connected inductively to the circuit of the main winding of such relay, and controlling such signal to indicate clear, caution and danger, when such relay is energized positively, negatively and deenerfgized respectively; a circuit for each of said polar neutral-retained relays including -neutralfretained armature pole changing contacts of such relay located at the next signallocation inA advance arranged so that the direction of current flow in such circuit is reversed when such relay in advance is deenergized, and means for deenergizing a particular relayif the block next in advance of such relay is occupied by a train.-

ing a neutral armature, a winding for the neutrai armature deriving magnetism inductively from the circuit of said main Winding, associated With each signal controlling such signal to indicate clear, caution and danger, When such relay is energized positively, negatively and de-energzed res ectively; and an energizing circuit for each of said relays including contacts operated by the neutral armature of the relay associated with the next signal location in advance and so connected to a source of direct current that the direction of current flow in such circuit is reversed When the neutral armature of the relay in advance is changed from an attracted to a detractcd position.

JERRY BENNETT. 

